1. Field of the Invention
The present invention concerns cable trays constructed by butt-jointing channel-section tray sections which have regularly spaced perforations in the bottom and side walls.
2. Description of the Prior Art
These cable tray sections are always supplied in predetermined unit lengths, regardless of the material from which they are made (metal, plastics, composite, . . . ) and the method of manufacture (bending and/or stamping, molding, extrusion, pultrusion, . . . ). The sections are usually butt-jointed by means of fishplates which have, facing a row of perforations, a row of hoops adapted to engage in at least two perforations of each of the two sections to be jointed and a locking comb member whose teeth are wedged in the hoops engaged in the perforations.
Installing a cable tray involves cutting sections to varying lengths, with the result that the position of the end of the section relative to the perforations is usually modified.
Consequently, to re-establish the pitch of the perforations with a conventional fishplate and comb, it is necessary to leave a gap between adjacent sections, which has the disadvantage of interrupting the desirable continuity of the cable tray.
An object of the invention is to avoid this drawback by eliminating the necessity to re-establish the pitch of the perforations.